PROTOPTERUS. 515 



head, so that it covers the head and body hke a veil." 

 These capsules, with the surrounding earth, have often been 

 transported from Africa to northern Europe, without injury 

 to the dormant life within. On emergence the animal 

 makes peculiar sounds, probably due to the forcible expul- 

 sion of air from the lungs through the lips. 



Two questions of much interest arise: — how does the encapsuled 

 animal breathe, and how is it nourished ? 



Although the red vascular appearance of the tail led Wiedersheim to 

 the opinion that caudal blood vessels might be the seat of a respiratory 

 interchange of gases, it is almost certain that air passes directly from 

 the mouth of the burrow, through the aperture of the capsule-lid (which 

 is produced inwards in a short pipe) to the external nostrils, and thence 

 to the lungs. 



The nourishment appears to be derived from a store of fat deposited 

 in the lymphoid tissue around the reproductive organs and kidneys, and 

 among the lateral muscles of the tail (cf fatty bodies in caterpillars, 

 amphibians, &c. ). Moreover, some of the muscles are replaced by fat, 

 and others undergo a pathological granular degeneration (cf lamprey). 

 To a certain extent, therefore, the dormant animal lives on its own tail. 

 It is probable that leucocytes aid in the absorption and transportation 

 of the degenerated muscles (cf tadpoles). 



A few of the anatomical characteristics of Protoplenis may now be 

 noted, following Prof W. N. Parker. 



The paired fins are filamentous, and seem degenerate when compared 

 with those of Ceratodus, having only one series of short lateral horny 

 rays on the cartilaginous segmented axis. The tail is symmetrical, and 

 ends in a filament which, like the end of the fins, is often bitten off; 

 often, however, there is a slight upward bending, which suggests a 

 heterocercal condition. Both tail and fins may be regenerated after 

 serious injuries. 



In the skin are very numerous mucus-secreting goblet cells, and there 

 are also (especially on the snout) multicellular glands, which are absent 

 from most fishes, though common in Amphibians, Reptiles, and 

 Mammals. There is a continuous lateral line, and apart from this there 

 are other integumentary sense organs on the head and various parts of 

 the body. There are taste buds on tongue and palate, olfactory organs 

 with posterior as well as anterior nares — the latter concealed by the 

 overhanging lips, relatively small, lidless eyes, and auditory organs. 

 "The apparently anomalous position of the nostrils is probably to be 

 explained as an adaptation to the habits of the animal in connection 

 with its summer sleep." 



There is a spiral valve in the large intestine ; the cloaca has an 

 associated " ciecum ; " the pancreas surrounds the bile-duct, and though 

 large, is almost hidden within the walls of the gut ; the spleen is also 

 large, but inconspicuous. Cilia are present throughout the stomach and 

 intestine, and there are no differentiated gastric or intestinal glands. 

 There is an unusually abundant investment of lymphoid tissue associated 

 with the gut, " which, during the period when Protopterus is, as it 



